Nonhomogeneous goods are often difficult to convey because the liquid substance tends to separate from the solid substance. If one uses a bucket conveyor or a similar device, then the liquid cannot be efficiently conveyed. If one uses a pump, difficulties arise with the solid component. It is nevertheless desirable in the case of liquid, nonhomogeneous, materials in tanks that the liquid and solid components remain mixed (homogenized). Particularly in the case of such material as grape mash, there occurs a separation of the components if the grape mash is stored in a horizontally positioned, cylindrical or approximately cylindrical tank. The must settles on the bottom and the pulp and peels float on top.
If it is desired to empty the grape mash from the tank by means of a pump, the must flows out downwardly and out of the floating, solid parts. Thus, an umpumpable mass of solid material is left. The use of agitators to keep the solid and liquid parts of such goods mixed has already been tried but known agitators work the grape mash too intensively and thereby develop further disadvantages in the wind-pressing step. Furthermore the known agitators consist of an undesirably large number of parts which makes cleaning thereof correspondingly complicated and time-consuming. However, cleaning thereof is required at least once a day. Further, the large number of structural parts increases the price of the known agitators. The large surfaces, corners and edges of the agitator elements which must be moved against the grape mash require in addition a substantial amount of force.
The basic purpose of the invention is to produce an agitator which is constructed simply and therefore inexpensively, which can be cleaned easily and in addition will not damage the goods which are being handled.
The invention attains this purpose by arranging in the tank a rotatable spiral of a small width and at a selected pitch.
Due to the fact that the narrow spiral circulates continuously only small amounts of the material to be agitated, there is achieved a protective treatment of the materials so handled, particularly referring to grape mash. Furthermore only a few arms are necessary for supporting the agitating spiral because the spiral itself comprises a closed structural member. The narrow spiral carries floating thick materials in the upper zone of the tank into the liquid at the bottom. On the other hand, it carries liquid upwardly on the opposite side and mixes it again with the thick materials floating on the top. This assures a constant good mixture (homogenization) of the materials to be agitated, particularly grape mash. Furthermore the agitator results in a very open structure with only a few parts which permits an easy and time-saving cleaning. Finally this agitator is constructed simply, with minimum materials and therefore inexpensively. Through the pitch of the spiral the materials to be agitated are led slowly and without damage to the discharge opening of the tank. This agitator is advantageously arranged near the bottom of the tank.
If the discharge opening is not at the end of the tank and if therefore parts of the spiral are positioned on both sides of the tank discharge opening, then the flights thereof have oppositely extending pitch to convey the material from both ends of the tank to the discharge opening.
The spiral blade can stand perpendicularly to the imaginary cylinder which it encloses. Advantageously, it, however, is positioned at an angle to such imaginary cylinder such that the outer edge of the blade, seen in direction of rotation, leads the inner edge. Due to the angle of pitch of the spiral, the goods, such as grape mash, to be agitated, are carried along still better and are treated more carefully.
Finally, according to a further embodiment of the invention the spiral can be constructed as a self-supporting structural part without a supporting shaft. In this manner, the cleaning of the agitator is made still easier.